My nephew wants to go Rat in his "71". Needs a crank. He is mystified by the "427" legend and history. I told him to go with a 4.0 stroke crank, just because of more cubes, and better piston selection. I feel the seat of pants feel he will like better. The car is for 90% street and 10% strip. He has a M-21, and factory Rect. port heads, and 4.11 rear. He also wants a Hyd. roller. Other than more revs from the 427 I can not see why he would want less cubes. Maybe if he reads opinions from other people he can make up his mind. Thanks.

If you need to buy a crank go with the 4.25 stroke and really have some fun. Tell him to put the "427" badges on everything and only he will know why it rus so good.... Heck I went with the "396" badges all over my car.

i have always run 454s but the next engine i build IS going to be a 427. the hot trend now is big bore short stroke, you get alot more for your money that way and a much more efficient combination. you put that 3.75 crank in there and bore it+.060 or +.100 and you have everything if not more than a 454 would be.and on top of it the car has a stick, maybe with an auto. you could go 454 that might make some sense.
john [img]graemlins/thumbsup.gif[/img]

i would say that there is not alot of different performance wise between the two motors in stock to mild form......i dont think any one here would be able to tell the difference if they was told to drive this car and guess which is it....is it a 427 or 454....just by the feel of the pants mind you.....some of you will get lucky and others would be off.... build according to your budget and what you have to work with......

i know alot of you would argue the point of more cubes but who is really going to know difference......im sure alot of you would drive my race car and would believe it to be a 454 at least because how fast it is....but what would you say if i told you it was a 396 and truely was....like i said many of you would not know the difference build what makes YOU happy not what others think you should build....besides who going to be driving it more.........

If he wants to build a 427 there will be no harm done, so let him do it. Too bad he wants a hydraulic roller - he'll miss out on the solid flat tappet/solid roller rpm capability of the 427. A 427 at 7,000+ rpm has a song of its own. Have him sell the rectangular port heads and get ovals instead. I cannot think of any sub 6,500 rpm 427 that would need the port volume of the rectangular port heads.

kinda the point i was trying to make,my friends 68 camaro with a 447 (100 over427) and my car 69 chevelle with a 468, both weighing the same, his went 10.16 and mine went 10.17 on the same day, but he probably had only 2500.00 in his motor and i had around 4grand in mine. and who is driving more? the nephew who is mystified with the 427s, right?
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That is two things I tried to explain to him, 1.) He be better off with 049 or 781 large oval ports for the street and 2.) That a solid flat tappet would be a better choice than a hyd. roller, a solid roller even better. He reads that GM put the Rect. heads on 396's, 427's, and the 454, and thinks that is what is needed for a fast car. But I told him that in the long run it is his money and car and having fun is the most important thing.

Years ago I had a 396 with basicly the same parts as my friends 454, both in 70 chevelles. I saw alot of his tail lights. The seat of the pants difference was even more dramatic. A 427 is a great engine and people go fast with them, its just hard to argue with cubic inches.

I have run a .060 over 396 for years with great success the motor is a 10.5:1 closed chamber oval port engine with an 850 DP,HEI, Isky 292/590 cam, steel roller tip rockers,torker intake manifold. with a TH400 and 3500 conv. In my 69 Malibu full body 3,600 lb car with 4:56 gears it has run consistent 11.60's not bad for a "baby rat"

Open mouth insert foot [img]graemlins/clonk.gif[/img] Didn't mean to step on any toes. I grew up in the 396 era of the early 70s. They were very popular back then. Had to build one, and I beat my share of 454s with it. But didn't beat too many with similiar setups.